Why Must Hemoglobin be Modified?

Hemoglobin is toxic to the human body. When the hemoglobin is encapsulated in the red blood cell it is a tetramer, but outside the red blood cell in the plasma it breaks into two dimers that travel through the blood steam quickly and create a toxicity in the kidneys. This is why hemoglobin must be modified by cross-linking or recombination.

Hemoglobin in the plasma causes the oncotic pressure to decrease but this can be prevented by increasing the concentration of the hemoglobin to 7 g/dl, stabilizing the oncotic pressure.

Hemoglobin removes the NO from the vessel walls causing vasoconstriction, shrinkage of the vessels.